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Category:Meeting Briefing Package/Handouts
MONTHYEARML24016A1762024-01-16016 January 2024 Integrated Safety, Security, and Safeguards Ffr Research Project ML23342A1642023-12-0808 December 2023 Networking and Information Technology Research and Development Program Software Productivity Sustainability and Quality (Spsq) NRC - Sushil Birla December 14, 2023 ML23292A0922023-10-30030 October 2023 Advanced Sensor and Instrumentation - NRC Research Status Update ML23298A0312023-10-26026 October 2023 Advanced Fuel Cycle Storage and Transportation Research ML23324A2702023-10-24024 October 2023 Session - Key Takeaways ML23324A2322023-10-24024 October 2023 S0P1 - Focht - 2023 NRC Workshop on Advanced Manufacturing Technologies for Nuclear Applications -Workshop Overview- ML23324A2332023-10-24024 October 2023 S0P2 - Focht - NRC AMT Activities Overview v2.0 ML23275A0022023-10-0505 October 2023 Domain Modeling & Domain Engineering an Enabler for Correct-by-Construction Design ML23272A0332023-09-29029 September 2023 Identifying Hazards in a System Design ML23264A0212023-09-28028 September 2023 Addressing Hazards from Common Causes in Engineering Di&C Systems Without Diverse Designs - State-of-the-Art ML23264A0252023-09-20020 September 2023 September 20, 2023 - Dent Presentation - John Mckirgan - Research Activities in Support of Digital Engineering in Nuclear Technology ML23256A0102023-09-18018 September 2023 State-of-the-art Approaches to Reduce the Potential for CCF in I&C Systems Conditions to Avoid the Need for Diversity in Design ML23251A0572023-09-13013 September 2023 Session 1 - Importance of Standards, Opportunities for Participation and Collaboration ML23251A0582023-09-13013 September 2023 Session 2 - International Initiatives on Codes and Standards ML23251A0592023-09-13013 September 2023 Session 3 - Development of Risk-Informed and Performance-Based (Ripb) Standards ML23251A0602023-09-13013 September 2023 Session 4 - Development of Standards for Artificial Intelligence Systems ML23242A1182023-09-0707 September 2023 Research Challenges and Opportunities in the Safety Assurance of Nuclear Reactors ML23248A2142023-09-0606 September 2023 Reactor Safety: Regulatory Objectives & Framework ML23242A0032023-08-31031 August 2023 Reactor Protection System for the Virtual Ford Nuclear Reactor Designed-in Assurance ML23194A1872023-07-20020 July 2023 Assurance: Cyber Physical Systems - Exploring International Collaboration ML23192A0712023-06-29029 June 2023 Assurance: Cyber Physical Systems - Exploring International Collaboration ML23152A1802023-06-14014 June 2023 13 - NRC - Materials Harvesting Activities ML23067A3402023-03-0707 March 2023 Presentation, N-853-1 Proposed Revision Technical Exchange with Electric Power Research Institute Welding and Repair Technology ML22322A0432022-11-18018 November 2022 Regulatory Research on the Aging Management of Structures, Systems and Components in Nuclear Power Plants for Second License Renewal, Presentation Slides ML22280A1122022-10-0707 October 2022 Session 3 - Rapid Qualification of AMT Components - Is It Rocket Science? ML22266A2682022-09-28028 September 2022 Session 6 - Recent and Planned Developments and Updates in Codes and Standards Part 2 ML22266A2662022-09-28028 September 2022 Session 4 - Regulatory Initiatives for Streamlining Code & Standards Endorsement ML22174A3232022-06-27027 June 2022 NRC Presentation: Harvesting, an Overview and Historical Perspective ML22143A8292022-05-25025 May 2022 11 - 2022-05 NRC-Industry Meeting - Raynaud - Favor Update ML22143A8362022-05-25025 May 2022 18 - 2022 NRC-Industry Mtls Exchange Mtg - NRC Xlpr Presentation ML22143A8422022-05-25025 May 2022 27 - Zorita Ril ML22139A1372022-05-20020 May 2022 Presentation Slides for ACRS May 20, 2022 Meeting - ASME Sec XI Div. 2 ML22132A2992022-05-17017 May 2022 Staff Presentation for May 17, 2022 Public Meeting ML22102A1062022-04-0101 April 2022 ARPA-E Presentation-04-01-22-FINAL Research Activities in Nuclear Innovation and Regulation ML22060A0052022-03-0101 March 2022 Dt Public Meeting - NRC Slides ML21319A3902021-10-29029 October 2021 ASTM-E08-04 - Wrs Workshop - NRC Slides ML21230A3602021-08-18018 August 2021 NRC-EPRI Capstone Reports ML21230A3662021-08-18018 August 2021 Xlpr Seminar_Applications_Code Case N-770 ML21230A3642021-08-18018 August 2021 Xlpr Metamodeling ML21230A3632021-08-18018 August 2021 Xlpr Maintenance ML21230A3612021-08-18018 August 2021 Xlpr LOCA Frequencies Presentation for Xlpr User Group ML21230A3572021-08-18018 August 2021 LBB Studies V4 ML21230A3562021-08-18018 August 2021 International Pfm Code Benchmark ML21230A3582021-08-18018 August 2021 Lessons Learned - Xlpr Run Optimization ML21217A2602021-08-10010 August 2021 11 - NRC - Ni-Alloy Crack Growth ML21217A3042021-08-0909 August 2021 06 - NRC - Pfm Regulatory Guide Update - August 10-11, 2021 Industry/Nrc Materials Programs Technical Information Exchange ML21200A0722021-07-20020 July 2021 ACRS July 20 - Overview of ASME Section III Division 5 and NRC Review and Potential Endorsement.Pdf ML21173A1762021-06-22022 June 2021 Presentation to ACRS - Scheduled for June 25th 2021 in Pdf ML21011A2462021-03-0808 March 2021 RIC 2021 Digital Exhibit: Engagement with Codes & Standards Organizations 2024-01-16
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MONTHYEARML24016A1762024-01-16016 January 2024 Integrated Safety, Security, and Safeguards Ffr Research Project ML23342A1642023-12-0808 December 2023 Networking and Information Technology Research and Development Program Software Productivity Sustainability and Quality (Spsq) NRC - Sushil Birla December 14, 2023 ML23292A0922023-10-30030 October 2023 Advanced Sensor and Instrumentation - NRC Research Status Update ML23298A0312023-10-26026 October 2023 Advanced Fuel Cycle Storage and Transportation Research ML23324A2702023-10-24024 October 2023 Session - Key Takeaways ML23324A2322023-10-24024 October 2023 S0P1 - Focht - 2023 NRC Workshop on Advanced Manufacturing Technologies for Nuclear Applications -Workshop Overview- ML23324A2332023-10-24024 October 2023 S0P2 - Focht - NRC AMT Activities Overview v2.0 ML23275A0022023-10-0505 October 2023 Domain Modeling & Domain Engineering an Enabler for Correct-by-Construction Design ML23272A0332023-09-29029 September 2023 Identifying Hazards in a System Design ML23264A0212023-09-28028 September 2023 Addressing Hazards from Common Causes in Engineering Di&C Systems Without Diverse Designs - State-of-the-Art ML23264A0252023-09-20020 September 2023 September 20, 2023 - Dent Presentation - John Mckirgan - Research Activities in Support of Digital Engineering in Nuclear Technology ML23262A9842023-09-19019 September 2023 MPA Seminar 2023 - Evaluation of Molten Salt Compatibility with Structural Alloys ML23256A0102023-09-18018 September 2023 State-of-the-art Approaches to Reduce the Potential for CCF in I&C Systems Conditions to Avoid the Need for Diversity in Design ML23251A0602023-09-13013 September 2023 Session 4 - Development of Standards for Artificial Intelligence Systems ML23251A0592023-09-13013 September 2023 Session 3 - Development of Risk-Informed and Performance-Based (Ripb) Standards ML23251A0582023-09-13013 September 2023 Session 2 - International Initiatives on Codes and Standards ML23251A0572023-09-13013 September 2023 Session 1 - Importance of Standards, Opportunities for Participation and Collaboration ML23242A1182023-09-0707 September 2023 Research Challenges and Opportunities in the Safety Assurance of Nuclear Reactors ML23248A2142023-09-0606 September 2023 Reactor Safety: Regulatory Objectives & Framework ML23242A0032023-08-31031 August 2023 Reactor Protection System for the Virtual Ford Nuclear Reactor Designed-in Assurance ML23206A1592023-07-27027 July 2023 Identifying Hazards from Engineering Digital I&C Systems: State of the Art ML23194A1872023-07-20020 July 2023 Assurance: Cyber Physical Systems - Exploring International Collaboration ML23187A4762023-07-0606 July 2023 Advanced Sensors and Instrumentation NRC Research Status Update Presentation at Npic&Hmit 2023 ML23187A4862023-07-0606 July 2023 NRCs Digital I&C Research for Application in Nuclear Power Plants Status Update Presentation at Npic&Hmit 2023 ML23192A0712023-06-29029 June 2023 Assurance: Cyber Physical Systems - Exploring International Collaboration ML23146A0952023-06-14014 June 2023 11 - NRC - Favpro ML23146A1022023-06-14014 June 2023 18 - NRC - Xlpr Update ML23152A1802023-06-14014 June 2023 13 - NRC - Materials Harvesting Activities ML23060A1432023-03-16016 March 2023 Lund - TH23 - v6 ML23067A3242023-03-0707 March 2023 Presentation - Code Case N-894 Alternative Rules for Repair of Classes 1, 2, and 3 Austenitic Stainless Steel Piping with Thermal Fatigue Cracking ML23067A3402023-03-0707 March 2023 Presentation, N-853-1 Proposed Revision Technical Exchange with Electric Power Research Institute Welding and Repair Technology ML23019A1502023-01-19019 January 2023 Public Q&A and Closing ML23019A1672023-01-19019 January 2023 Review of 06/14/2022 Meeting ML23019A1562023-01-19019 January 2023 NRC Use Cases for LOCA Frequency Estimates ML23019A1692023-01-19019 January 2023 Walk-In and Agenda for Meeting with the EPRI to Discuss Use of the Extremely Low Probability of Rupture Code for LOCA Frequency Estimates ML22321A0212022-12-0202 December 2022 Alloy 690/52/152 Thermal Aging: NRC Plans and Activities ML22322A0432022-11-18018 November 2022 Regulatory Research on the Aging Management of Structures, Systems and Components in Nuclear Power Plants for Second License Renewal, Presentation Slides ML22174A3232022-06-27027 June 2022 NRC Presentation: Harvesting, an Overview and Historical Perspective ML22143A8422022-05-25025 May 2022 27 - Zorita Ril ML22143A8292022-05-25025 May 2022 11 - 2022-05 NRC-Industry Meeting - Raynaud - Favor Update ML22143A8362022-05-25025 May 2022 18 - 2022 NRC-Industry Mtls Exchange Mtg - NRC Xlpr Presentation ML22139A1372022-05-20020 May 2022 Presentation Slides for ACRS May 20, 2022 Meeting - ASME Sec XI Div. 2 ML22132A2992022-05-17017 May 2022 Staff Presentation for May 17, 2022 Public Meeting ML22102A1062022-04-0101 April 2022 ARPA-E Presentation-04-01-22-FINAL Research Activities in Nuclear Innovation and Regulation ML22060A0052022-03-0101 March 2022 Dt Public Meeting - NRC Slides ML21319A3902021-10-29029 October 2021 ASTM-E08-04 - Wrs Workshop - NRC Slides ML21230A3632021-08-18018 August 2021 Xlpr Maintenance ML21230A3662021-08-18018 August 2021 Xlpr Seminar_Applications_Code Case N-770 2024-01-16
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Text
Leak-Before-Break Studies NRC Phase 1 LBB Report/ Plans for LBB Phase 2 and EPRI Report August 18, 2021 1
Introduction
- Application of xLPR to a real-life problem: Impact of primary water stress-corrosion cracking (PWSCC) on a Reactor Vessel Outlet Nozzle (RVON) for a Westinghouse 4-loop Nuclear Power Plant
- Largest number of same weld type with Alloy 82/182 within leak-before-break (LBB)-approved line segments in the U.S. nuclear fleet
- Coordinated effort by NRC/RES and EPRI via a memorandum of understanding, with the following goals:
- 1. Develop a defensible strategy of xLPR use for risk-informed decision making
- 2. Initiate the first phase of a system-level analysis considering a loop or a whole unit
- 3. Test different Quantities of Interest (QoIs) as criteria for decision-making
- Program to be followed by a second phase considering other weld locations and combination of results at the system level 2
Problem considered
- Reactor Vessel Outlet Nozzle (RVON) for a generic Westinghouse 4-loop pressurized-water reactor
- 34 inches diameter (0.869 m)
- 2.6 inches thickness (0.0663 m)
- Temperature : 320.5°C
- Pressure 15.41 MPa
- Focus on circumferential cracks (axial cracks considered in sensitivity run)
- Simulation time : 80 years (timestep : 1 month)
- Large number of uncertain inputs (e.g.,
welding residual stresses (WRS), crack initiation parameters, crack growth parameters) 3
Quantities of Interest
- Probability of rupture with leak rate detection
- Probability of Leak Rate Jump: going from less than 10 gpm to more than 50 gpm in one timestep
- Probabilistic LBB ratio (critical crack size over detectable leakage crack size)
- Similar to the deterministic ratio in NRC Standard Review Plan Section 3.6.3
- Estimated for each realization leading to a distribution of the LBB ratio
- Distribution of time from detectable through wall crack to rupture
- Outputs in blue are directly estimated in xLPR - other outcomes need postprocessing but can be done easily in Excel 4
Probabilistic Approach
- Considered acceptance threshold is 10-6 occurrence per reactor year.
- Equivalent to probability of occurrence of 8 x 10-5 over 80 years
- Sample size considered between 70,000 and 100,000 should lead to respectively 5 to 8 events on average, if the probability is higher than the threshold
- Analysis conditional on having a crack at time 0 use sample size of 5,000 since probability of having crack over 80 years is in the 10-3 range
- Large amount of data saved, so a single probabilistic run was not practical
- 7 replicates of 10,000 to 15,000 sample size, each with different random seeds, were run and combined
- Crack leak rate, inner length, outer length, and critical ratio extracted to estimate the composite QoIs 5
Reference results (1/2)
- Probability of leak rate jump and rupture with leak rate detection too low to occur over 100,000 realizations
- Good on a regulatory standpoint since it shows the risk is below the acceptable range. Not ideal on a scientific standpoint as there is no quantification of the risk
- Rather, alternate QoIs are presented (P(1st crack),
P(1st leak) and P(rupture) without inspection or leak rate detection) 6
Reference results (2/2)
- Composite QoIs give results for different criteria (for instance 1 gpm and 10 gpm leak rate detection limits)
- Results are conditional on having pipe rupture and do not reflect this probability 10 gpm 10 gpm 1 gpm 1 gpm Time between detectable LBB ratio leak rate and rupture 7
Sensitivity Case: Impact of WRS Profile (1/2)
- New WRS mean profile with similar uncertainty applied
- Larger mean at insider diameter leads to higher probability of 1st crack
- Lower minimum reduces probabilities of 1st leak and rupture relative to the reference value Still, no ruptures with leak rate detection or leak rate jump events 8
Sensitivity Case: Impact of WRS Profile (2/2)
- Stronger impact on LBB ratio and LBB time lapse than for the reference case
- Use of multiple metrics gives more insights on scenario differences and increases confidence in the results 9
Sensitivity Case: Impact of Temperature
- Change in operating Still, no ruptures with leak rate detection or leak rate jump events temperature (deterministic value) from 320.8°C to 330°C
- Considered large change since the same temperature is applied through the whole 80-year simulation time
- Temperature affects initiation and growth, thus impact in all three metrics presented 10
Conclusions and Perspectives
- This study helped identify bugs and enhancements for xLPR (they will be fixed in Version 2.2) but overall, the code is ready to be used for regulatory decisionmaking
- Beyond the already available outputs, composite QoIs can be defined and calculated in post-processing without too much effort
- This study helped identify advantages and drawbacks for each QoI considered and showed the benefit of using multiple metrics
- This first analysis serves as a good basis to extend the process to other weld types (pressurizer surge line, reactor coolant pump ) and estimate risk at the system level 11